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Dalvik’s future replacement debuts in Android 4.4 KitKat, currently an experimental feature

The days of Dalvik might finally be winding down! Google's upcoming replacement runtime, ART, has now debuted in Android 4.4 KitKat. Currently Dalvik is still set to default, as ART is still very much in the experimental stages.
November 6, 2013
Android 4.4 KitKat

With Android 4.4 KitKat we have already seen quite a few new features including a modernized phone dialer, improved Google Now integration and faster multi-tasking. What you might not know is that deep inside KitKat there is also a hidden experimental feature that could forever change Android as we know it.

The new ‘feature’ goes by the name ART, as in Android Runtime. The goal of ART is to replace the aging Dalvik runtime, and is the fruits of over two years of work from Google.

While the first whispers about ART residing in KitKat go back to as early as last week, earlier today Android Police dug in a bit deeper to bring us a bit more information on what to expect and how to even test out the new runtime for yourself. Although ART isn’t turned on by default in Android 4.4 KitKat, it can be found within Developer options and can easily be switched on.

Of course there’s a reason Google has yet to make ART the default runtime. Right now, ART is still very much a work in progress, and Google warns that using it can cause system instability and can risk breaking apps.

So what makes ART potentially better than Dalvik?

With Dalvik, each and every time you open an app, a bunch of code needs to be compiled using the Just-in-Time compiler. This method takes a pretty hefty toll on your smartphone, as the process itself isn’t particularly efficient.

That’s where ART comes in. Instead of doing all this compiling work each and every time you open an app, ART uses a Ahead-of-Time compilation method that pre-compiles bytecode into machine language from the moment that you first install an app.

Because ART no longer needs to run all that interpreted code when starting up an app, the end result is that apps will launch quicker and will run more smoothly. While ART will likely get even better as Google continues to work on it, in the current KitKat build, ART reportedly was able to cut down execution times in half for nearly every application thrown at it.

With apps launching more efficiently, less stress is put on our mobile device’s processors and other components, and this leads to not only a better Android experience but less power usage as well, meaning that ART could indirectly help out by extending battery life.

On the downside, the AOT method takes up a bit more space when installing apps and results in a much longer installation time for more complex apps — though it sounds like the benefits far outweigh these minor annoyances.

If you are currently running Android 4.4 KitKat, testing out ART is as easy as going to Settings> Developer Options> Select Runtime.

Keep in mind that ART isn’t fully ready for primetime just yet, so test it at your own risk. It’s also worth noting that if you are using a ROM, there is a chance that the gapps package could cause serious crashing issues — so again, proceed at your own risk.

Looking ahead

While it’s nice to see Google allowing developers to test out ART on Android 4.4 KitKat, the bigger takeaway is that the days of Dalvik are almost over and we could soon be looking at a new era for Android, one where some of the so-called app/UI lag is behind us for good.

When can we expect ART to arrive as the default in Android? While we’d love to say something definitive like “you’ll see it in Android 4.5”, the honest answer is that it will arrive when it’s ready. That said, if Google has enough confidence to let folks take it for a spin in KitKat, the official transition to ART might not be terribly far off.

What do you think of ART based on what we currently know? Excited about the idea of seeing a Dalvik-free Android future?